Pump for power lifted implements



1943. c. E. FRUDDEN ,332,629

PUMP FOR POWER LIFTED IMPLEMENIS Filed Aug. 15,- 1941 2 Sheets-Sheet 1 I 2 Sheets-Sheet 2 'lll Q. E. FRUDDEN PUMP FOR POWER LIFiED IMPLEMENTS Filed Aug. 15, 1941 via 2% w 8 Patented Oct. 26, 1943 PUMP FOR POWER LIFTElJ DIPLEMENTS Conrad E. Frudden, Wauwatosa, Wis., assignor'to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.,

a corporation of Delaware Application August 15, 1941, Serial No. 407,023 6 Claims. (01.103-41) This invention relates to improvements in power lifting means for devices which require frequent raising and lowering during their operation and particularly to a hydraulic power liftfor implements and the like to be drawn by an automotive vehicle having an engine supplying power for operating the lif Internal combustion engine driven tractors for both farm and industrial uses are frequently pmwith various implements which must be inports and having the implements mounted thereon for the purpose of securing lifting of the implements whenever desired. Means must, however, beprovided to avoid production and transmission of pressure to the servomotor when lifting is completed.

It is therefore an object of the present invention to provide a hydraulic lift for implements to be operated by an automotive vehicle in which a two cylinder reciprocating piston type pump is continuously operated from a constantly driven shaft of the vehicle and is provided with means permitting lifting, holding and lowering of the implements at thewill of the operator.

Another object of the invention is to provide a hydraulic lift for implements to be operated by automotive vehicles in which a single control member operates both a relief valve and a bypass between the two cylinders of a piston pump.

Another object of the invention is to provide a hydraulic lift for implements to be operated by an automotive vehicle in which member operates both a relief valve and a bypass between two cylinders of a piston pump and has positive end positions for lifting and lowering of the implement and an impositive midposition for holding the implement in the lifted position.

Another object of the invention is to provide a hydraulic lift for implements to be operated by a single control automotive vehicles in member operating both pass between two cylinders of a piston pump must be manually brought to the position for lifting the implement but is automatically returned to the position for holding the implement in raised position. i:

Objects and advantages other than those above set forth will be apparent from the following description when read in connection with the accompanying drawings, in which:

Fig. 1 is a fragmentary view of approximately the right half of the rear end of an, internal combustion engine driven tractor having an implement supporting and rocking shaft mounted thereon and showing the mounting of the pump on a power take-off shaft housing of the tractor and the connection of a hydraulic ram with the rock shaft for the implement:

.Fig. 2 is a plan view of a two cylinder reciprocating pump with the upper portion of the power take-oil casing removed to show the manin which the pump is mounted on the casing and is driven from the power take-off shaft of the tractor;

which a single control Fig. 4 is a vertical sectional view taken longitudinally through the pump adjacent one cylincylinder reciprocating pump, on

the discharge from the cylinders; Fig. 5 is a vertical sectional view taken on, the

the pump to the ram;

Fig. 6 is a vertical sectional view taken longishaft for controlling the means for operating the shaft;

Fig. 7 is aside elevation of the shaft for controlling the application of pressure from the a relief valve and a by-' to the ram and for assisting in operating the relief valve for controlling the discharge of pressure from the ram;

Fig. 8 is a transverse sectional view of the control shaft taken on the lineVIIL-VIII of Fig. 7

Fig. 9 is a transverse sectional view of the control shaft taken on the line IX IX of Fig. 7;

Figs. 10, 11 and 12 are somewhat diagrammatic views of the control shaft operating meansand the relief valve and the control shaft in section to show the positions of the several parts when the implement is to be lifted;

Figs. 13, 14 and 15 are somewhat diagrammatic views of the control shaft'operating means and the relief valve and the control shaft in section to show the positions of the several parts when the implement is to be held in the lifted posi-' tion; and

Figs. 16, 1'1 and 18 are somewhat diagrammatic L views of the control shaft operating means and the relief valve and the control shaft in section to show the position of the several parts when the implement is to be lowered down to the work surface.

Referring to the drawings by characters of reference, numeral 2| designates the right rear wheel of a tractor having a pneumatic tire 22 mounted thereon. The wheel is driven by way of the usual gear drive enclosed in-a housing 23 and power is transmitted from the usual engine by way of a rear axle enclosed in the housing 24. A power take-off shaft 26 is driven fromthe transmission unit and extends fromthe housing 21 mounted on the transmission unit 25 and frame member 3|. Pressure is applied from the pump 28 to the ram 31 and is discharged from the ram to the pump by way of a flexible tube 38. It will be understood that the ram comprises only a cylinder closed at one end and a piston movable in the cylinder and extending therefrom'through a seal at the other end of the cylinder.

The pump 28 has a body 4| inwhich are drilled a pair of holes serving as cylinders in which .pistons 42 and 43 are reciprocable. The pistons are under the action of springs, as at 44, compressed between the end of the cylinder and a shoulder on the piston 43 to force the pistons out of, the

inlet ball valve 56 and 51 and fills the portion of the cylinder containing the springs 44. The next rotation of the shaft 26 and cams 5| and 52 alternately drives pistons 42 and 43 into the cylinders against the compression of springs 44 and ejects oil from the cylinders past the discharge valves 58 and 59. Discharge valves 58 and 59 are opened by the discharge pressure from t the cylinders against] the action of compression springs 6| and 62 severally mounted on supports 63 and 64 threaded into the valve body 4|. Oil under pressure (up to 3500 pounds per square -inch pressure) is then forced through the passage about the spring support into a passage 65 through the pump body 4| and through the tube 38'andbelow the'piston of the ram to force the "'ram'piston outwardly and rock the shaft 33 as above stated. It will be noted that cams 5| and 52 are so designed that the cylinder volumes 7 sides of the shaft andth'e'grooves are joined by a cylinder into contact with cam follower arms 46 and 41 pivotally mounted on the pump body .4|. Each of the cam follower arms 46 and 41 is pro vided withrollers as at 48 and 49 for contact (see Fig. 2) with the surface of cams 5| and 52 mounted on the take-off shaft 26 within the housing 21. As the shaft 26rotates, cam 5| and 52 oscillate cam followers 46 and 41 back'and fourth and alternately push the pistons 42 and 43 into the cylinder following each outward movement of the pistons under the action of the springs 44. Each outward movement of the pistons produces a partial vacuum in the inlet pipe 53 and inlet passage 54 to draw oil into the cylinder from the housing 21. The oil lifts the bore 14. Grooves 12, 13 and bore 14 areso' located thatthe grooves may be brought into registry with passages 16, .11 from the pump cylinders (see Figs. 4, 11, 12, 14, 15,17 and 18). -When suchregistry is obtained, the pressure producing stroke of one piston occurs while the other piston is producing a vacuum. Oil i then merely forced through the registering passages from one cylinder to. the other without producing any material pressure, without dischargingjfromthe pump and without; opening of the suction valves to admit more oil. Shaft 1| also has'a groove 8| and a flat surface 82 milled therein outwardly from'the bore 14 to provide a drain and a seat respectively fora thimble 83 fitting into a bore. joining the pump discharge passage 66 and-the hole for-th'e shaft 1|. The thimble receivesaspring 84 su'p-.

porting a plunger 86 on which is held a. ball 81 for seating in the bore. Bal1' 81 controls the dischargeof oil through a passage 88 to the' exterior of the pump body 4| when lt'is necessary to ventpressure discharged by the pump in ex cess of the spring resistance pressure 'andwhen the implement is to be lowered' which requires that the oil in the ram be discharged; l r Y H ,The end of controlshaftJlxextend's from the pump body 4 and is I sealed therein by a i'fiexible' seal ring 91 heldat oneend 0!!"13118 shaftbya spring clip 92 and held'awayfrom the shaft at the other end by telescopic flanged casings 93 and 94, The extending end of: thelscontrol shaft has fixedly mounted thereon a, {plate "95 and a plate91 loosely-mounted thereon; Plates '96 and 91' are both slotted on the same-.am and their movement is limitedto a relativelyi'small arc by studs .98 extending through-the slots and threaded into the body 4| of the pun'ipl IJPIateST is' fric' tionally held against the plate 951133 a1: s'pririg I 99 connected at one end-to one of the studs' 38' and connected at the other end witii the-plate 91.- The spring is prevented from. slipping'off theend of the shaft by a washer I0 I .pinne'abmthe outer end of the shaft. Plate 96 is provided with' a's'uit ablehandle I I02 extending adiacent thes'eat of aasaeaa '3 the tractor and has formed thereon avprojectlon position resting fully on the fiat which relieves I03 engaging with the plate 91 when'the'p'late is the compression of the spring 84; and the ball moved beyond a predetermined amount. plunger 86, and ball 81 move downwardly to open The operation and control of the power lift the connection between the pump discharge pasdevice will be more clearly understood by refer- 5 sage 66 .and the venting discharge passage 88: ence to Figs. to 18, inclusive. Figs; 10, 11 and The oil therefore flows through the orificefor- 12 show the position of the parts'whentheimplemerly closed by the relief ball valve 81 and disment is to be lifted. Fig. 10 shows thepo'sitions charges such oil back, to take-ofi" housing. 21. 1

into which the plate 96 is pulled by the oper'ator Pressure in the tube 38 and the ram 31 is thereto secure the deliveryof pressure from the "pump 10 fore released and the weight of the implement to the ram and therefore secure the lifting of brings the implement back to the work surface.

the implement. Projection I03 jfrorn plate 85 It will be noted that the relief valveis opened by first engages the edge of the'plate91 and causes relieving a spring pressure on the ball-rather rotation thereof until the opposite ends of the thanby acting against the high pressure fluid in slots in both plates engage the studs 98 at one the ram cylinder. Therefore, only a verysmall end of the arc of plate rotation. During moveeffort is required to secure opening ofthe relief ment of the plate 91, spring 09 istension'ed and valve. The forward end of theshaft 1| has been the operator must hold the plates in the posibrought to the-positionshown in Fig. 18 in which tions sh wn a ainst th sprin t ns on as lo the grooves 12,. 13 and the bore 14 are still. in as the lifting action is to continue. The above '2 registry with the by-passes16 11 fromthe pump rotation of plates 96'and 91 and of control shaft cylinders, and oil merely flows back, and :forth 1| is without effect on the relief ball valve 8 between the cylinders as above stated, upon conbecause thimble 3 h reof me 'I n h timed operation of the pump, without building pe ph y of Shaft a Shown n Fig. 11. up pressure and hence without in any way affect- Grooves 12, 13 on control shaft H 'are turned to mg operation of the ram while the implement is brin the bore 14 out of registry with the passages to be retained in its lowered position. 16 and 11. Continued reciprocatlonof the p It will be seen from the above description, that piston 2 an 3 th r e for es oil under presthe present structure provides a positive pressure sur h h h d charge passage 66 and tu e producing pump having .two pistons operated 38 into ram 3 e a p e is henforced from cams on a power take-off shaft with a single outwa d t rotating e k shaft until control member operating both. arelief. valve the implement connected therewith is lifted "to and opening or closing a, bypass between the its i hest point. If the operato inadvertently cylinders. The pump can therefore be constantcontinues to 110161 the COIltIOl shaft 1| in the DOSi- 1y operated to produce the high pressure retion Shown, further p mping ction producing 'quired without any danger of building up excess oil pressure will only force the relief ball valve pressure d ith ut interference ith t pres- 81 01f its seat against the action of its spring to sure operated lifting device at any time. The

vent the excess oil P s e k to the casing I control member is movable into three positions 21 by way of the passage 88. of which the end positions are positively fixed If the implement is o be held the lifted 40 by stops and in which the midposition is deterposition, the operator releases the handle I02. mined only by Spring tension which t t Tension on the pring 9-9 then rotates p at s -9 1y returns the control member from the lifting and 91 into the ml p i n h n n Fig-13, that end position to the holding midposition. Such is, the plates are moved until the studs 88 are at lifting position is the only position in which inthe midpoint in the slots of plate 96 and at the advertent retention of the control member' can end 0f the slots of plate 91. Shaft 1| then mOVeS produce overpressurgwhich js vented by the r into the position shown in Fig. 14 in which the lief v l ball valve 81 ,is still held in its seated position Although but one embodiment of the present capable of releas n e ce s p essu e ut eta invention has been illustrated and described, it ing the pressure already produced in the pump will be apparent to those skilled in the art that i ch p ssage 66, the tube 38 and the cylinder various changes and modifications may be made of the ram ,1. The forward end of the shaft H therein without departing from the spirit of the has been moved into the position shown in Fig. invention or from the scope ofv the appended 15 to bring the grooves 12, 13 and the bore 14 claims. into registry with the pump by-pass passages It is claimed and desired to secure by Letters 16 and 11. Continued operation 01' the pump Patent: therefore merely forces oil at low pressure backl. A high pressure pump comprising a pluward and forward through the by-pass'clue to the rality of cylinders, a piston for each of said cylincoincident suction and discharge strokes of the ders, a discharge passage for fluid from each of pump pistons in the several cylinders. No fursaid cylinders, a bypass passage interconnecting ther pressure therefore is produced by the pump said cylinders, means for controlling flow of but the pressure already produced is retained and fluid through said bypass passage, a relief valve holds the implement in the lifted position. controlling pumped fluid, and means controlling When the implement is to be lowered from the both said flow controlling means and said relief lifted position, the handle I02 is pushed to rotate valve. plate 96 into the position shown in Fig. 16 in 2. A pump comprising a plurality of cylinders, which studs 98 again act as stops but the plate pistons for each of said cylinders, a discharge 96 has now moved so that the ends of the slots passage from each of said cylinders, a bypass opposite those engaged in Fig. 10-, are now enpassage interconnecting said cylinders, means gaged. The studs therefore determine the two intersecting said bypass and having a passage end positions of the plates and the shaft and therethrough movable into and out of registry positively position the parts f r i t n and l l' with said bypass to control flow of fluid therein o h imp m Shaft TI is moved to the through, a relief valve controlling pumped fluid, osi io own i a 1 in w i e shaft fiat and means controlling both said fiow control 82 allows thimble 83 to move downwardly into 35 an and aid r n f valv A 3. A pump comprising a plurality of cylinders, pistons for each of said cylinders, a discharge passage for conducting fluid from said cylinders, a bypass passage interconnecting said cylinders,

.a control member controlling flow of fluid through said bypass, a relief valve controlling opening of said discharge passage, said control member also controlling opening of said relief valve, and means for selectively actuating said control member to positions for closing both said bypass and said relief valve, for opening said bypass only, and for opening both said bypass and said relief valve.

4. A pump comprising a body having a plurality of cylinders, pistons in said cylinders, a discharge passage for conducting fluid from said cylinders, a bypass passage interconnecting said cylinders, a control member extending from exteriorly of said pump body into said bypass for controlling flow of fluid therethrough, a relief valve controlling opening of said discharge passage, said control member also controlling opening of said relief valve, a plurality of plates mounted on the exterior end of said control member and having pairs of superposed arcuate slots therethrough, and studs extending through the slots to severally fix the positions of said control member respectively for closing both said bypass and said relief valve and for opening both said bypass and said relief valve.

5. A pump comprising a body having a plurality of cylinders, pistons in said cylinders, discharge passages for conducting fluid from said cylinders, a bypass passage interconnecting said cylinders, a control member extending from exteriorlyof said pump body into said bypass for controlling flow of fluid therethrough, a relief valve controlling opening of said discharge passage, said control member also controlling opening of said relief valve, a plurality of plates mounted .on the exterior end of said control member, and a spring interconnecting said plates to flx the position of said control member for opening only of said bypass.

6. A pump comprising a body having a plurality of cylinders, pistons in said cylinders, discharge passages for conducting fluid from said cylinders, a bypass passage interconnecting said cylinders, a control member extending from exteriorly of said pump body into said bypass for controlling flow of fluid therethrough, a relief valve controlling opening of said discharge passage, said control member also controlling opening of said relief valve, a plurality of plates mounted on the exterior end of said control member and having pairs of superposed arcuate slots therethrough. studs extending through the slots to severally fix the positions of said control member respectively for closing and for opening both said bypass and said relief valve, and a spring interconnecting said plates to automatically fix the position of said control member for opening only of said bypass upon release of the plates from the position where both said bypass and said relief valve are closed.

' CONRAD E. FRUDDEN. 

